Grinding machine



J. N. HEALD ET AL GRINDING MACHINE 2 Sheets-Sheet 1 Original Filed duly14. 1922 I Nov. 5, 1929.

J. N. HEALD ET AL GRINDING mourns Nov. 5, 1929.

Original Filed July 14. 1922 2 sinus-Sheet 2 *9 4, the latter beingdriven at high. speed by" Reissued Nov. 5, 1929 UNITED STATES PATENTOFFICE JAMES H. OF WORCESTER, AND ALBERT TURNER, OF SHREWSBUBY, MASSA-CHUSETTS, ASSIGNORS TO THE HEALD MACHINE COMPANY, OF WORCESTER, MAS-SACHUSETTS, .A CORPORATION OF MASSACHUSETTS GRINDING Original no:1,583,351, dated May 4, 1926, Serial No. 574,940, filed July 14, 1922.

' filed February 7, 1927. Serial No. 166,576.

The present invention relates to grinding machines. The inventionresides in the novel combination and arrangement of parts hereinafterfully described, of especial utility in the constructionand operation ofa grinding machine adapted to operate on cylindrical or similarsurfaces, but equally applicable, in certain features, to a' grindingmachine adapted to operate on internal or concave surfa s, or on planesurfaces.

In t e accompanying drawings,

Fig. '1 is a view inside elevation of such a grinding machine, accordingto the present invention.

Fig. 2 is an end view of said machine.

Fig. 3 is a top plan view.

Fig. i is an enlarged detail sectional view of the headstock of themachine.

Fig. 5 is a schematic view, partly in section, of certain fluid pressuredevlces used for reciprocating the work.

Fig. 6 is a detail view of the oscillating valve member. a a

Fig. 7 is a detail view of the valve cap or closure. y Fig. 8 is atransverse sectional view of the fluid pressure control and reversingmech anism. I

Like reference characters referto like parts in the diiferent figures. vThe improvements forming the sub ect matter of the present invention arehere shown in connection with a plain grinding machine of the usualconstruction, embodying a suitable frame or base 1 which carries theusual wheel slide 9,; the latter being trans- I versely movable in ways3, 3, provided by the machine frame. The slide 2 has journalled thereinthe spindle of a grindlng wheel -any suitable means, such as a belt 5yvhich connects pulley 7;. The .on a shaftS,

. countershafting, likewise not shown in any event, the arrangement issuch that the machine is self-contained as regards the drive of thegrinding wheel 4, and the pull on the MACHINE Application for reissuewheel spindle by the driving devices is there fore downward, thussupplementing the weight of the wheel slide 2 in the mainte-. nance forthe latter of a firm seat on the frame or base of the machine. The usualadjustment of the wheel slide 2 in the ways 3, 3 for the purpose ofpositioning the wheel. for different sizes of work is accomplished by ahand wheel 9 on the front of the machine, the'latter operating through ascrew or other means, not shown, to obtain the crossfeed of the wheel 4.The wheel driving belt '5 1s caused to accommodate itself to the variouspositionsof the grinding wheel by a spring pressed tightener pulley 10,which is end, the machine frame provides longitudinal Ways 11, 11 for asliding table 12, the movement of which, according to the presentinvention, is obtained by a fluid pressure controlling and reversingmechanism, of the type, for instance, disclosed in the co ingapplication of Drake and Hubbell, erial No. 528,118, filed January 9,1922. As shown in Fig. 5, and as disclosed in detail in the aforesaidcopending application, the table end- 12 is suitably connected, as. by avvrod 13, to a doubleacting piston 14, contained in a fluid pressurecylinder 15.- The piston 14 is actuated by the admission of fluid underpressure to one end or the other of the cylinder 15, the fluid pressurebeing forced by a pump 16into a supply pipe 17 which delivers to aforming no part of the present invention, is described and claimed insaid copending ap- -va1ve device 18, the construction ofwliich,

plication. The valve device 18 comprises a rotatable reversing valvemember 57 (see Figs...61'and 8) keyed to a shaft 58, a stationary member59 having ports 60 and 61 and a valve cap 62 (seeFig. 7 having ports ,63i and 64. Port 60 is'in communication with.

return pipe 65 whereas port- 61 is in communication with supply pipe 17.Port 63 is in communication with pipe 19 and port 64 with pipe 20. Therelation of members 59, 57 and 62 is clearly shown in the sectionalviewFig. 8, and if we assfime that valve' member 57 of Fig.6is projectedwithout axial displacement onto stationary member 59 of Fig. 5, then thecontrolling devices for the table 12 are in the neutral, position. Valvemember 57 has three passes 66, 67 and 68.

Pass 66 is always in communication with port 61 and so receives, at alltimes, the fluid entering at port 61. In the above described neutralposition, pass66 is also in communication with both ports 63 and 64 andat the same time passes 67 and 68 communicate with port 60 and also withports 63 and 64. In this neutral position, then,

the fluid will be shunted frLm pipe 17 through pass 66 to ports 63 and64 through passes 67 and 68 to port 60, thence back by' return pipe 65.At the same time, both pipes. 19 and 20 are connected throu h ports 63and 64 to the freely moving flui so that the fluid in cylinder 15 willnot be constrained and the table 12 may therefore be moved by hand.

A lever 21 is also keyed to shaft 58, the upper end of this lever beingfitted with a knob or handle, or the like. Assuming now that the lever21 is moved to the position shown in Fig. 1, the valve member 57 will beI rotated in a clockwise direction, thus breaking the connection betweenpass 67 ar port 63 and also breaking the connection between pass 66 andport 64. It will be obvious then that the only outlet from port 61 forthe fluid will be by way of pass 66 to port 63 and pipe 19, which willcause the piston 14 in c" linder 15 to move to the right carrying t erod 13 and table 12. This will force fluid at theright of piston 14 outof cylinder 15 through pipe 20 entering port 64 where it is constrainedto pass through pass 68 to port and so back by way of return pipe65. Itwill be obvious, without further description, that movement of handle 21to the left and consequent rotation of valve member 57 dogsengage the ina counterclockwise direction, causes fluid to enter cylinder 15 by wayof pipe 20 and leave cylinder 15 by way of pipe 19, because of thesymmetrical arrangement of members 57, 59 and 62.

As described, the reversing valve device 18 is operable, as shown inFigs. 1 and 8 herein, by the direction control lever 21, the

"latter having a disengageable pin 69,.Znormally located in a slot of 'arocking mem-' ber 22 whose upper 'end projects intoflthe path'of a pairof adjustable dogs 23 and 24 carried by the ta le12. These .stops orember 22 alternately, whereby to reverse the direction of travel of thetable 12 at each engagement; their longitudinal adjustment determinesthe throw, or

dogs:-.. Member 22 is pivoted on shaft 71 and also has connected to it aplunger 72 forced downward by a spring 73. The end of plunger 72-is Vshaped and operates in connection with a stationary cam member 74,whereby to snap member 22 quickly to the right or left after it crossesthe central or vertical position.

Mounted on the reciprocating table 12 are the usual worksupportingdevices, here shown as a head stock 25 and a tail stock 26, the sameproviding suitable centers 27, 27 for the support between them ofthework. The head stock 25 and the tail stock 26 are both directlysupported for longitudinal adjustment in suitable ways 28,- provided bya member 29,

the latter adapted to swivel bodily-on the table 12 in order to vary theangularity of the axis of the work, ,in the presentation of same to thegrinding wheel 4.

For procuring rotation of the work on the axis provided by the centers27 27 the head stock 25 supports and carries an adjustable speedelectric motor 30, the shaft 31 of which, as shown in Fig. 4, has a wormgear connection 32 with a countershaft 33, the latter being suitablyjournalled in the head stock and adapted to impart rotation by the wormgearing 34 to a driving plate 35, coaxial with the centers 27, 27 andengageable with the.

ly, the starting button 37 is'engaged, thus causing the motor 30 toimpart'rotation to the work at a speed which is determined by thepositionof the control lever 40 of a speed adj usting device 41 in thecircuit of motor 30. In

this position of lever 36, a valve 42 inthe fluid pressure supply pipe17 leading to valve 18 is held open by alink connection 43 with saidlever36. Also, by means of 'a link connection 44, a valve 45 in waterpipe 46 is moved into open position, as shown in Fig. 2, thus insuring asupply of water for,the grinding operation. When the lever 36 is throwninwardly to engage the button 38 for topping the motor 30, the valves 42and 45 ar losed by their respective links 43 ajnd'4 4; this shuts ofithe pressure fluid, thus stopping the movement of table 12, and at thesame time prevents wastage of water afterthe discontinuance of grinding.

For the dressing and truing of the wheel 4;, by means, mond 47 on thetail-stock 26, the above described control mechanism affords specialadvantages; by holding the lever 36' in an intermediate position, so asnot to engage the running and thus the work, during the pediate positionof the lever 36 is accompanied by a partial opening of both the valves42.

. and 45, through their respective link connections 43 and 44; thisinsures a supply of water for the wheel during the dressing operaof thetable 12to carry the dresser 47 back and forth in contact with theperiphery of the wheel. It is to be noted that this last-named result isobtained, through the medium of valve 42, without in any way disturbingthe predetermined setting of speed control valve 48, associated with thereversing valve device ,18 and manually adjustable, (by its attachedhandle, Fig. 8), as described in the aforesaid copending application ofDrake and Hubbell, to controlthe speed at which the table 12 is movedback and forth during any given grinding operation. As a result of this,after the wheel has been dressed, the grinding operation can be resumedat the same speed previously determined upon, since the full completedmovement of lever 36 into contact with starting button 37 causes valve42 to move to its wide-open position.

In the use of the machine for grinding by straight inward cuts,involving no reciprocation of the Work in contact'with the wheel, it

is necessary only to shut off the valve 48 completely, thusdiscontinuing the fluid pressure supply. Thereupon, the movement oflever 36 to starting position insures the desired supply of water forthe grinding. operation and also insures the desired rotation of thework,in the absence, however, of 'any table travel whatsoever.

As shown most clearly in Fig. 5, .the'inVention affords an automaticmeansgfor insuring a lowered speed of travel for the table, just priorto reversal thereof; the lowering of the speed taking place at thatmoment when the plunger 72 reaches the apex of the stationary cam member7 4, at which instant the rocking member 22 is about to spring to ltsextreme position'to definitely make the pressure fluid active on theother side of the piston to reverse the direction of travel of thetable. In this manner the detrimental shocks incidental to reversal athigh speeds are avoided. For this purpose is provided a' lever 49,pivoted at 50 to the fixed framework, and carrying on its free end,adjacent to the rocking member 22, a roller 51. {Said roller 51 forinstance, of a suitable, diastarting button 37, the motor 30 is keptfrom,

riods when the Wheel is being dressed, is not sub ect to rotation.However, this interme- .of its stroke.

tion, and also, a throttled-down reciprocation stroke by said ta le.

lies in the path of inclined cam surfaces 52 and 53 formed,respectively, on the table dogs 23 and 24. Thesurfaces 52 and 53 are sodisposed, with relation to the dogging surfaces proper, as to makecontact with the roller 51, during the reciprocations of table 12, justprior to the engagement of member 22 by one or the other of saiddoggingsurfaces. In this way, just before each reversal of the table, the freeend of lever 49 is depressed; in consequence of which, by means of link54, a valve 55 in fluid pressure supply pipe 17 is partially closed.This throttles the fluid pressure supply, and thus decreases the speedof travel of the table, as the latter approaches each end This automaticspeed reduction insures a smooth reversal of the table, with a uniformamount of over-run at each end of the stroke, since the speed impartedjust before reversal is invariably a lowered. speed of travel,regardless of the s This is especially. valuable in the grinding of longwork of relatively small diameter,'where a high table speed is requiredfor efiicient operation and where the problem of smooth reversal is adifficult one. Furthermore, this slowing up of the table travel is mostdesirablewhcnever is to be encountered at the end ofthe surface beingground, since it prevents the withdrawal of the work in the absence of acomplete revolution in contact with the wheel at the a shoulder point ofreversal and thus insures the production of a true diameter at thatpoint.

As shown-in Fig. 1, the machine provides,

in addition to the motor starting button 37 (normally operated by thelever'36) a start ing button 56, which is so connected in the motorcircuit with the speed adjustment device 41 as to produce, when helddepressed,

a very slow rotation ofthe motor 30. This allows the driving plate 35 tobe brought to any desired position, for facilitating the disposal in themachine, or the removal therefrom, of work that is, for various reasons,difficult to handle.

ton 56 pressed in, for testing purposes, or to determme whether or not1t 1s runnlng true,

or whether it has been sprung in the grind-.-

means operable by fluid-pressure for reciprocating said table, anelectric motor carried by said table for rotating the work, and a Inaddition, the work may be made to rotate slowly by holding this but-'said table, anelectric motor carried by said starting and stoppinglever for said motor, adapted to control, simultaneously, the fluidpressure supply. a

3. In a grinding machine, the combination with a table for supportingthe work, of means operable by fluid pressure for reciprocating saidtable, an electric motor carried by said table for rotating the work,and a levermovable into opposite positions for respectively starting andstopping said motor and opening and closing the fluid pressure supply,said lever, in an intermediate position, adapted to throttle said supplywithout starting said motor.

5. In a grinding machine, the combination with a table for supportingthe work, of means operable by fluid pressure for reciproeating saidtable, an electric motor carried by said table for rotating the work, agrinding wheel, means for supplying water to said wheel, and a levermovable into opposite positions' for respectively starting and stoppingsaid motor and opening and closing the fluid pressure supply and thesupply of water to said wheel, said lever, in an intermediate position,adapted to throttle said fluid pressure supply and furnish water to saidwheel without starting said motor.

6. In a grindin machine, means operable by fluid pressure orreciprocating the work, a control device adjustable to vary the speed ofsaid reciprocation, an electric motor, re:

- ciprocating with the work, for imparting rotation thereto, and astarting and stopping lever for said mot-or adapted, in an inter-.mediate position, to throttle the speed ofreciprocation of the work,independently of the setting of said control device, and withoutstarting said motor. I

7. In a grinding machine, a table adapted to be 'reciprocated by flpidunder pressure, a reversing valve for the pressure fluid, connections,including dogs on said table for actuating said reversingvalve,-*throttling valve means separate from said reversing valve, andmeans on said table adj acent said dogs to actuate said throttling valvemeans, said .last two means being adapted to check the flow of fluidjust prior to the actuation of said reversing valve by saidflogs,whereby a high speed table may be reversed with a small but definitelyfixed overrun, said table resuming speed immediately after reversal,

8. In a grinding machine, a table reciprocab'le by fluid under pressure,a reversing valve for the pressure fluid, dogs on said table foroperating said reversing valve, thereby to procure the reversals of saidtable, a second valve independent of said reversing valve for thecontrol of said pressure fluid,

and means on said table adjacent said dogs.

for actuating said second valve to reduce the flow of pressure fluidslightly in advance of .each actuation of said reversing valve by saiddogs, thereby to lower the speed of said table at a moment prior to eachreversal of its travel. a

9. In a grinding machine, a table re- 1 sure fluid, and-,meansoperatedby'said table for actuating said second valve to reduce'the flow ofpressure fluid slightly in advance of each actuation of said reversingvalve by said dogs, thereby to lower the speed of said table at a momentprior to each reversal of its travel.

10. In a grinding machine, a reciprocable table, fluid pressure meansemploying a substantially non-compressible fluid for operating saidtable, a reversing valve for said fluid, means for operatin saidreversing valve to procure reversals 0 said table, and means todecelerat-e the table to given low speedatthe moment that the reversingvalve first produces an efl'ect on the fluid under pressure in the actof reversing the motion of the table, said decelerating means actingthrough control of the'fluidunder pressure and having an unvarying'effect on the table to enable the length of the table stroke to bemaintained at an adjusted length despite variations in speed of thetable travel between the limits of the stroke.

stantially non-compressible fluid for operating said table, a tablereversing member, table dogs adapted for coaction with said reversirigmember for reversing the direction 0 travel of said table, a reversingvalve actuated by said reversing member, and means automatically actingon the fluid under pressure and effective at that moment when thereversing valve first starts to exert its efl'ect upon'the fluid tobring the flow of fluid operating the table to a definitelow volume.

12. In a grinding machine, a reciprocable table, fluid pressure meansemploying a substantially nonscompressible fluid for operating saidtable, means for reversing the direction ofgtra'vel of said table, andmeans'op erating ohithe flow'of fluid under pressure priorlto thereversalthereohfor causing itto operate the tixblethiough agiven rangeof speed in its negative acceleration 'prior to the reversal thereof,thus to maintain a predetermined length of the stroke of said tablenotwithstanding variations in table inertia due to changes in tablespeed.

JAMES N. HEALD. ALBERT TURNER.

